For other meanings of the abbreviation, see: NMT.

NMT (Nordisk MobilTelefoni or Nordiska MobilTelefoni-gruppen, Nordic Mobile Telephone in English) is a mobile phone system that was specified by the Nordic telecommunications administrations (PTTs) starting in 1970, and opened for service in 1981 as a response to the increasing congestion and heavy requirements of the manual mobile phone networks: ARP (150 MHz) in Finland and MTD (450 MHz) in Sweden, Norway and Denmark. NMT is based on analog technology (first generation or 1G) and two variants exist: NMT-450 and NMT-900. The numbers indicate the frequency bands uses. NMT-900 was introduced in 1986 because it carries more channels than the previous NMT-450 network. 0G refers to pre-cellular mobile telephony technology. ... Push to talk, commonly abbreviated as PTT, is a method of conversing on half-duplex communication lines, including two-way radio, by pushing a button in order to send, allowing voice communication to be transmitted from you, and releasing to let voice communication be received. ... Manual Tone Shift (MTS) was one of the earliest mobile telephone protocols. ... The Improved Mobile Telephone Service (IMTS) is a pre-cellular VHF/UHF radio system that links to the PSTN. IMTS had originally only sixteen channels and were prone to network congestion and interference by others keying up their radios while a converstaion was already occurring on a channel. ... The Advanced Mobile Telephone System was a 0G method of radio communication, mainly used in Japanese portable radio systems. ... Autotel (also called PALM, or Public Automated Land Mobile) is a radiotelephone service which was the missing link between earlier MTS/IMTS and later cellular telephone services. ... ARP (Autoradiopuhelin, Car Radio Phone in English) was the first commercially operated public mobile phone network in Finland. ... 1G (or 1-G) is short for first-generation wireless telephone technology, cellphones. ... This article is about AMPS, the North American mobile phone system standard; AMPS is also an initialism for the All Media and Products Survey published by the South African Advertising Research Foundation. ... hicap is a mobile techonology which has a consumer interface with a wide variety of industry references. ... 2G (or 2-G) is short for second-generation wireless telephone technology. ... The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world. ... Integrated Digital Enhanced Network, commonly refered to as iDEN, is a mobile communications technology, developed by Motorola, which provides its users the benefits of a trunked radio and a cellular telephone. ... IS-54 and IS-136 are second-generation (2G) mobile phone systems, known as Digital AMPS (D-AMPS). ... This article needs to be cleaned up to conform to a higher standard of quality. ... Personal Digital Cellular (PDC) is a 2G mobile phone standard developed and used exclusively in Japan. ... 2. ... General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones. ... Wideband Integrated Dispatch Enhanced Network, or WiDEN, is a software upgrade developed by Motorola for its iDEN enhanced specialised mobile radio (or ESMR) wireless telephony protocol. ... A 2G mobile phone is a circuit switched digital mobile phone. ... CDMA2000 is a 3G mobile telecommunications standard that uses CDMA, a multiple access scheme for digital radio, to send voice, data and signaling data (such as a dialed telephone number) between mobile telephones and cell sites. ... Enhanced Data rates for GSM Evolution (EDGE) is a digital mobile phone technology which acts as a bolt-on enhancement to 2G and 2. ... 3G (or 3-G) is short for third-generation mobile telephone technology. ... W-CDMA (Wideband Code Division Multiple Access) is a type of 3G cellular network. ... This article needs to be cleaned up to conform to a higher standard of quality. ... FOMA, officially short for Freedom of Mobile Multimedia Access, is the brand name for the 3G services being offered by Japanese mobile phone operator NTT DoCoMo. ... CDMA2000 is a 3G mobile telecommunications standard that uses CDMA, a multiple access scheme for digital radio, to send voice, data and signaling data (such as a dialed telephone number) between mobile telephones and cell sites. ... TD-SCDMA (Time Division Synchronous Code Division Multiple Access) is a 3G mobile telecommunications standard, being pursued in the Peoples Republic of China by the Chinese Academy of Telecommunications Technology (CATT), Datang and Siemens AG, in an attempt to develop home-grown technology and not be dependent on Western... The term 3. ... High-Speed Downlink Packet Access or HSDPA [[1]] is a new mobile telephony protocol. ... HSUPA, High-Speed Uplink Packet Access, is a data access protocol for mobile phone networks with extremely high upload speeds up to 5. ... HSUPA, High-Speed Uplink Packet Access, is a data access protocol for mobile phone networks with extremely high upload speeds up to 5. ... 4G (or 4-G) is short for fourth-generation the successor of 3G and is a wireless access technology. ... NMT may mean: Nordic Mobile Telephone New Mexico Tech non-metallic conduit boots with a non-metallic toe Northwest Marine Technology NMT Medical NMT Corporation Toronto New Media Trainers Alliance NMT International Shipping Network Management Technologies NMT Group National Mobile Television Nuremberg Military Tribunals National Meningitis Trust Not More Then... 1981 (MCMLXXXI) is a common year starting on Thursday of the Gregorian calendar. ... ARP (Autoradiopuhelin, Car Radio Phone in English) was the first commercially operated public mobile phone network in Finland. ... An analog or analogue signal is any continuously variable signal. ... 1G (or 1-G) is short for first-generation wireless telephone technology, cellphones. ... 1986 (MCMLXXXVI) is a common year starting on Wednesday of the Gregorian calendar. ...

The technical principles of NMT were ready by year 1973 and specifications for base stations were ready in 1977. The NMT specifications were free and open, allowing many companies to produce NMT hardware and pushing the prices down. The success of NMT meant a lot to Nokia (then Mobira) and Ericsson. Initial NMT phones were typical portable phones: one could definitely move them, but they were usually intended for car use. Latter-day models (such as Benefon's) were as small as 100 mm and weighed only about 100 grams. Nokia Corporation NYSE: NOK is one of the worlds largest telecommunications equipment manufacturers. ... Ericsson () is a Swedish telecommunications equipment manufacturer, founded in 1876 as a telegraph equipment repair shop by Lars Magnus Ericsson. ... Benefon is a company well known from the early mobile era as a mobile telephone maker for NMT and, later, GSM standards. ...

The network was opened in Sweden and Norway in 1981, and in Denmark and Finland in 1982. Iceland joined in 1986. However, curiously for a mobile phone standard that has the word "Nordic" in it, the first commercial service was introduced in Saudi Arabia on September 1st 1981 to 1200 users, one month before Sweden.

The NMT network has mainly been used in the Nordic countries, Switzerland, the Netherlands, Slovenia, Croatia, Bosnia, Baltic countries and Russia but also in the Middle East and in Asia. The introduction of digital mobile networks such as GSM has reduced the popularity of NMT and some of the Nordic phone companies have suspended their NMT networks (e.g. Sonera's NMT network was suspended on December 31, 2002 in Finland). The NMT network (450 MHz) however has one big advantage over GSM which is the range; this advantage is valuable in big but sparsely populated countries such as Iceland. In Iceland, the GSM network reaches 98% of the country's population but only a small proportion of its land area. The NMT system however reaches most of the country and a lot of the surrounding waters, thus the network is popular with those traveling in the mountains and fishermen. The Nordic countries (Greenland not shown) The Nordic countries is a term used collectively for five countries in Northern Europe. ... The Baltic Sea The terms Baltic countries, Baltic Sea countries, Baltic states, and Balticum refer to slightly different combinations of countries in the general area surrounding the Baltic Sea. ... A map showing countries commonly considered to be part of the Middle East The Middle East is a region comprising the lands around the southern and eastern parts of the Mediterranean Sea, a territory that extends from the eastern Mediterranean Sea to the Persian Gulf. ... World map showing Asia (geographically) Asia is the central and eastern part of Eurasia and worlds largest continent. ... Not to be confused with Get Some Mates The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world. ... TeliaSonera AB is the result of a merger between the Swedish and Finnish telecommunications companies, Telia and Sonera. ... December 31 is the 365th day of the year (366th in leap years) in the Gregorian Calendar. ... 2002(MMII) is a common year starting on Tuesday of the Gregorian calendar. ...

The cell sizes in an NMT network range from 2 km to 30 km. With smaller ranges the network can service more simultaneous callers; for example in a city the range can be kept short for better service. NMT used full duplex transmission, allowing for simultaneous receiving and transmission of voice. Car phone versions of NMT used transmission power of up to 15 watt (NMT-450) and 6 watt (NMT-900), handsets up to 1 watt. NMT had automatic switching (dialling) and handover of the call built into the standard from the beginning, which was not the case with most preceding car phone services, such as the Finnish ARP. Additionally, the NMT standard specified billing as well as national and international roaming. ARP (Autoradiopuhelin, Car Radio Phone in English) was the first commercially operated public mobile phone network in Finland. ... Roaming is a general term in wireless telecommunications that refers to the extending of connectivity service in a network that is different than the network with which a station is registered. ...

A disadvantage of the original NMT specification is that voice traffic was not encrypted. So anyone willing to listen in would just have to buy a scanner and tune it to the correct frequency. As a result, some scanners have had the NMT bands "deleted" so they could not be accessed. This is not particularly effective as it isn't that hard to obtain a scanner that doesn't have these restrictions; it is also possible to re-program a scanner so that the "deleted" bands can be accessed. Later versions of the NMT specifications defined optional analog scrambling which was based on two-band audio frequency inversion. If both the base station and the mobile station supported scrambling, they could agree upon using it when initiating a phone call. Also, if two users had mobile stations (=mobile phones) supporting scrambling, they could turn it on during conversation even if the base stations didn't support it. In this case audio would be scrambled all the way between the two mobile stations. While the scrambling method was not at all as strong as encryption in newer digital phones, such as GSM, it did prevent casual listening with scanners. Scrambling is defined in NMT Doc 450-1: System Description (1999-03-23) and NMT Doc 450-3 and 900-3: Technical Specification for the Mobile Station (1995-10-04)'s Annex 26 v.1.1: Mobile Station with Speech Scrambling - Split Inversion Method (Optional) (1998-01-27). In cryptography, encryption is the process of obscuring information to make it unreadable without special knowledge. ... In telecommunications, a scrambler is a device that transposes or inverts signals or otherwise encodes a message at the transmitter to make the message unintelligible at a receiver not equipped with an appropriately set descrambling device. ... Not to be confused with Get Some Mates The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world. ...

NMT also supported a simple but robust integrated data transfer mode called DMS (Data and Messaging Service) or NMT-Text, which used the network's signalling channel for data transfer. Using DMS, also text messaging was possible between two NMT handsets before SMS service started in GSM, but this feature was never commercially available except in Russian and Polish NMT networks. - Another data transfer method was called NMT Mobidigi with transfer speeds of 380 bits per second. It required external equipment.

NMT signalling transfer speeds vary between 600 and 1200 bits per second, using FFSK (Fast Frequency Shift Keying) modulation. Signaling between the base station and the mobile station was implemented using the same RF channel that was used for audio, and using the 1200 bit/s FFSK modem. This caused the periodic short noise bursts, e.g. during handover, that were uniquely characteristic to NMT sound. Frequency-shift keying (FSK) is frequency modulation in which the modulating signal shifts the output frequency between predetermined values. ...